Pressure: when is too much and why?

[35WhelenAI]

I'm not trying to create a urinary Olympiad or any type of negative debate.

The thread is about pressure and I'm going to stick to it at this point.

 

[bmart2622]

After you came in and stirred the pot now you're all about staying on topic!!!!

 

[jfk69]

Why shoot those calibers?

Because the caliber is excellent when loaded properly. The .280 comes immediately to mind as one of those grossly under loaded cartridges in factory ammo due to the 760 and 7600 being chambered in it for introduction. Great round when loaded for a bolt action. Not everyone wants to shoot the same cartridges as the crowd.

 

[35WhelenAI]

Disagreement is not stirring the pot. Check out the definition, I won't tell you what it is because you wouldn't want to hear it, I'd be putting words in your mouth. There's plenty to back up what I've said about bigger cases, and plenty to back up about the other things I've shared. As well, lots to back up counter points on the other side of some things as well. That's why it's a discussion. I'll keep the discussion to bigger cases for the same caliber instead of more pressure moving forward.

 

[Choupique]

.280 comes immediately to mind as one of those grossly under loaded cartridges in factory ammo due to the 760 and 7600 being chambered in it for introductio

Why not get a 7 mag instead?

I guess I'm just not understanding the logic for venturing off the book. Somebody developed that data with a strain gauge or crush gauges. It's going to be relatively accurate for your rifle. All you've got to go by are visual and tactile clues which are hardly scientific. If book max speed is too slow, why not get something with a bigger case? It's 2024, there's about 18 different options for every caliber we have now.

I'm not arguing that it can't be done safely. I just dont see the reason for doing it.

 

[bmart2622]

Because you can make the given cartridge faster and still be safe if you choose to

 

[Harvey_NW]

Why not get a 7 mag instead?

I guess I'm just not understanding the logic for venturing off the book. Somebody developed that data with a strain gauge or crush gauges. It's going to be relatively accurate for your rifle. All you've got to go by are visual and tactile clues which are hardly scientific. If book max speed is too slow, why not get something with a bigger case? It's 2024, there's about 18 different options for every caliber we have now.

I'm not arguing that it can't be done safely. I just dont see the reason for doing it.

All SAAMI ammo is loaded to a specific functional COAL, you change that dimension and you can change the dynamics of the pressure curve, which they don't publish data for. They also have to make sure that ammo will shoot in every factory cut chamber on the market with tentatively zero risk to the consumer.

Without getting too scientific, most of the time you can seat the bullet much farther out, add more powder, and voila more performance. Also a lot of factory ammo is loaded with available powders that may not be an optimal burn rate for that cartridge, so there's another opportunity to improve.

In some cases (7 PRC and Federal ammo comes to mind) it's pretty good stuff and you might be splitting hairs trying to beat it. But with a lot of older chamber designs the load data is pretty anemic, and you can make big improvements just by loading with optimal components. Especially if you start customizing chamber dimensions for those particular components.

 

[jfk69]

Why not get a 7 mag instead?

I guess I'm just not understanding the logic for venturing off the book. Somebody developed that data with a strain gauge or crush gauges. It's going to be relatively accurate for your rifle. All you've got to go by are visual and tactile clues which are hardly scientific. If book max speed is too slow, why not get something with a bigger case? It's 2024, there's about 18 different options for every caliber we have now.

I'm not arguing that it can't be done safely. I just dont see the reason for doing it.

Who says I’m trying to make it faster?? Where in my post did I say I was hot rodding anything? Try following along here. Book values are actually quite fine with me. A 140 grain bullet in a Norma factory whitetail loading chugs along at 2800 fps in my rifle. A 139 grain Hornady Interlock over a book loading of 4831 does 2990 fps. You don’t see the difference here? They underload factory .280 to accommodate the pumps and auto loaders. The .280 should do everything the .270 does, but they neuter the factory loadings. Understand? If I didn’t reload, I would not achieve what the .280 is capable of with factory ammo because the factory doesn’t want the liability of blowing someone’s pump Remington. Get it, or should I write in crayon? And fwiw, I have a 7 mag.

 

[Choupique]

Where in my post did I say I was hot rodding anything.

Well, the sidebar conversation you inserted yourself in was specifically about hotrodding. Perhaps I should pose my questions in crayon?

They underload factory .280 to accommodate the pumps and auto

I find that hard to believe since those rifles were available in .270/.30-06/.35 whelen.

But, what I'm trying to understand is why this community is both deathly focused on practicality at all costs and simultaneously pushing the limits on reloads. Its not isolated to here either. It seems reloaders are hard wired just to see how fast they can make it go.

Id expect the reliability-obsessed to be going the african route- bigger tapered cases for lower pressure for given performance.

 

[jfk69]

Well, the sidebar conversation you inserted yourself in was specifically about hotrodding. Perhaps I should pose my questions in crayon?



I find that hard to believe since those rifles were available in .270/.30-06/.35 whelen.

But, what I'm trying to understand is why this community is both deathly focused on practicality at all costs and simultaneously pushing the limits on reloads. It’s not isolated to here either. It seems reloaders are hard wired just to see how fast they can make it go.

Are you not following along? I AM USING BOOK VALUES. I am not “pushing” anything. I am not exceeding book values. But the book gives me almost 200 fps more than factory. I don’t care “what you believe”, look up the history of the .280 and why it never took off. It was severely under loaded to account for the pumps and auto loaders. My original response to you was “why shoot those calibers”. I gave you a very good example and why folks would want to. All you’ve done is ignored what I was saying and start some BS that I’m “going over book”, when I’ve been clear that I’m not. But for some reason you want to turn this into a pissing match and die on that hill. I’d suggest you learn more about other cartridges than your mainstream favorites.

 

[bmart2622]

I doubt youll understand it but Ill give you another example....I load my kids 300wm with 200gr ABs. Nosler data lists a max load of H1000 at 78.0grs with a velocity of 2851 fps with a 24" barrel. I seat the bullet long load it with 78.5 grs of H1000 and get absolutely ZERO pressure signs( got a very faint ejector swipe at 79.5gr) with a velocity of 3012fps. Why wouldn't I take the extra velocity when I can do so safely without all the added expenses that come along with buying a new rifle and all the reloading components that go with it?!?!

 

[Choupique]

doubt youll understand

Yea, I don't understand why increasing risk of popped primers/stiff bolts/stuck cases in inclement conditions are worth an extra whatever FPS going over book max gets you. If those extra FPS are necessary, why not use something with a bigger case?

Sorry for pissing in yalls cheerios. I'll see myself out.

 

[bmart2622]

Because I dont want a bigger cartridge!!! I want to safely maximize the one I have!!! You mention several times you are new to reloading yet you want to continue to argue with people have been doing it successfully without issues for decades!!!

 

[Castle Rock]

Id expect the reliability-obsessed to be going the african route- bigger tapered cases for lower pressure for given performance.

That is fundamentally wrong, tapered cases react worse to pressure and cause extraction issues

Yea, I don't understand why increasing risk of popped primers/stiff bolts/stuck cases in inclement conditions are worth an extra whatever FPS going over book max gets you. If those extra FPS are necessary, why not use something with a bigger case?

Sorry for pissing in yalls cheerios. I'll see myself out.

Stop being such a drama queen

 

[35WhelenAI]

I have an M70 SM Classic in 300 Win Mag. Had the bolt stop shortened, drilled out the sheet metal filler in the magazine box and put in a magnum length follower. With the generous throat of that rifle, a useable COAL of 3.600" was attainable with the bullets I use.

Like bmart, I was able to work up a load at a higher velocity, with no pressure issues at a higher charge weight because the cartridge dynamics are changed for the better to allow that.

Not something for a new reloader, but well within what experienced loaders can safely expect to accomplish and be safe.

 

[Harvey_NW]

Yea, I don't understand why increasing risk of popped primers/stiff bolts/stuck cases in inclement conditions are worth an extra whatever FPS going over book max gets you. If those extra FPS are necessary, why not use something with a bigger case?

Sorry for pissing in yalls cheerios. I'll see myself out.

It's not rocket science, and most of us test and take precautions. If it were that dicey, you'd hear of issues WAY more commonly, but usually when someone has an issue it's because of negligence and you can easily distinguish why it happened based on their load data or methodology.

Just to add salt to the topic I'm 11gr over published book max on my load in my 6.5 PRC

 

[A382DWDZQ]

I think I found a concrete answer to the “how much is too much” part:
“By the time it reached the Titanic wreckage, the Titan submersible would have been facing a pressure of between 375 and 400 atmospheres.”

 

[wyosam]

I think you’re purposely misunderstanding the move towards smaller cartridges. Ryan Avery has burned out 8 or 9 300 RUM barrels and he’s shooting a 6mm currentl because he “can’t cope with a modicum of recoil”? I hope you’re just joking around.

It’s been said enough times on this thread that if you want more velocity, use a different cartridge rather than try to get more than is safe out of a smaller one. It was a meaningful contribution the first time, but I can’t see the use of beating that horse at this point.

I’m pretty sure 99% of this (and every other) forum is beating dead horses.


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[Tell]

Maybe so. I can’t tell you how much I’ve learned since joining, and how much of a better shooter I am now. There’s a lot of knowledge in the collective of people using this site, and I’m very thankful for it. I grew up hunting and shooting, but I was like everybody else I knew. And when I look back to even a year ago, I’m an embarrassed at how ignorant I was. The information is out there, and the people on this site have an incredible amount of experience and I’m glad they’re willing to share it.

And thank God there are different viewpoints and disagreements. It gives us all a chance to use our heads for more than just a place to hang our ears. I’ve had quite a few good disagreements at the gunsmith’s shop where a lot of great shooters and hunters are always popping in. And I know we’ve all learned from them.

 

[AnotherAussie]

I've never experienced those problems with RL26 personally. Interesting. What's not interesting is this "Jake from unkown" that knowingly produces these "super hot" loads. That guy's an idiot.

Blanket statements can send an inaccurate message as case shape and volume can alter burning rates.

An easy example may be what we call a fast (ish) powder like 4198 (any of them) which is a fast powder, relatively speaking in a straight taper case like a .45/70 or .458 Winchester and yet it becomes or is considered, a slower burning powder when consumed in say a .222 Rem or .223.Rem case.

The smaller case volume and bottle necked case design allows the powder to burn more progressively.

Tbe same thing can happen or be noticed with Rel 26 just by changing the case size and shape. I have used it in a range of cartridges including .25/06, 280AI, 7mm Rem Mag, .30/06, .338 Winchester also with a range of bullet weights for each of those cartridges and its burning characteriatics may align differently with other powders also tested at the same sessions.

It pays to chronograph all test loads and record the data. Most importantly, review and digest your results and you will notice burning characteristics that ultimately teach you about powders in general and more specifically, how they compare and relate to the carteidges you have chosen for your own use.

If you like diving deep, put your results in a simple spread sheet and also record your group sizes, velocities next to tbe loads tried.

I take pics of these pages and save them on my phone for spare time viewing and reviewing. The more detail recorded the more helpful you will find it.